bsγ constraints on the minimal supergravity model with large tanβ

Howard Baer, Michal Brhlik, Diego Castaño, and Xerxes Tata
Phys. Rev. D 58, 015007 – Published 5 June 1998
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Abstract

In the minimal supergravity model (MSUGRA), as the parameter tanβ increases, the charged Higgs boson and light bottom squark masses decrease, which can potentially increase contributions from tH±, g̃bj and Zibj loops in the decay bsγ. We update a previous QCD improved bsγ decay calculation to include in addition the effects of gluino and neutralino loops. We find that, in the MSUGRA model, loops involving charginos also increase, and dominate over tW, tH±, g̃q̃ and Ziq̃ contributions for tanβ510. We find for large values of tanβ35 that most of the parameter space of the MSUGRA model for μ<0 is ruled out due to too large a value of branching ratio B(bsγ). For μ>0 and large tanβ, most of parameter space is allowed, although the regions with the least fine-tuning (low m0 and m1/2) are ruled out due to too low a value of B(bsγ). We compare the constraints from bsγ to constraints from the neutralino relic density, and to expectations for sparticle discovery at CERN LEP2 and the Fermilab Tevatron pp¯ colliders. Finally, we show that non-universal GUT scale soft breaking squark mass terms can enhance gluino loop contributions to bsγ decay rate even if these are diagonal.

  • Received 9 December 1997

DOI:https://doi.org/10.1103/PhysRevD.58.015007

©1998 American Physical Society

Authors & Affiliations

Howard Baer1, Michal Brhlik2, Diego Castaño3, and Xerxes Tata4

  • 1Department of Physics, Florida State University, Tallahassee, Florida 32306
  • 2Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109
  • 3Saint Leo College, St. Leo, Florida 33574
  • 4Department of Physics and Astronomy, University of Hawaii, Honolulu, Hawaii 96822

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Vol. 58, Iss. 1 — 1 July 1998

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